(a) Field of the Invention
This invention relates to a system and a method for treating wastewater from an oil and gas drilling operation and more particularly, but not by way of limitation, to an in situ system and method for treating an oil and gas well drilling fluid next to a drilling site and greatly reducing various types of contaminates held in suspension in the fluid and creating reusable water for addition drilling or discharge into a ground surface without violating any environmental state and federal regulations.
(b) Discussion of Prior Art
The treating and cleaning of drilling fluids from an oil and gas well drilling operation has long been a problem waiting for a solution. One typical solution is to allow the water to evaporate from a reserve pit next to the drilling rig. This solution can take years for the water to evaporate and prior to burying the remaining solids left in the pit. Also, animals and birds can be trapped in the pit during the time the pit is left open and exposed. There have been efforts employed to shorten the evaporation period by pumping the fluid through sprinklers. This effort works fairly well until the fluid becomes more and more viscous and the surface tension of the water becomes denser. At this time, less and less water evaporation occurs and the fluid becomes more dense until it can no longer be pumped effectively.
Chemical treatment of the drilling fluid can be employed to remove solids, but the water phase of the fluid is loaded with salt and dissolved minerals that make the water undesirable for further use. Solidification of the drilling fluid is an option, but this leaves a potential environmental danger if rain or surface water disturbs the site during subsequent time periods. Electrocoagulation has been employed in the past on drilling sites, but this method of treating the fluid leaves some of the minerals and almost all of the salt in the treated water.
Therefore and because the above-mentioned systems and methods are ineffective in removing all of the contaminates in a drilling fluid, there is no single technology that will solve the overall problem. The subject invention described herein uses a series of technologies to the solve the entire problem and convert the water from the drilling fluid into a very pure form that can be reused as a drilling fluid or discharged into the environment without damage thereto.
In U.S. Pat. No. 6,613,202 to Herbst et al. and U.S. Pat. Nos. 5,043,050, 5,423,962, 6,179,977, 6,241,861 and 6,746,593 to Herbst, the inventor of the subject invention, Robert J. Herbst describes different types of improved electrolytic, electrochemical and electrocoagulation water treatment processes for treating aqueous, contaminated solutions and precipitating various organic and inorganic materials suspended in the solution. The technology described in these patents is incorporated into various individual features of the subject in situ system and method of treating drilling fluids.
As mentioned above, none of the above mentioned prior art electrolytic, electrochemical and electrocoagulation systems and processes for treating wastewater disclose or teach individually or in combination the unique features of the subject invention which provides for treating large volumes of drilling fluids in situ with reliability and functionality not obtainable with other types of wastewater treatment systems.